激光烧蚀对石英/氰酸酯透波复合材料电性能的影响

Effects of laser ablation on electric properties of quartz fiber/cyanate resin wave-transmitting composite

研究激光烧蚀对石英/氰酸酯复合材料电性能的影响并揭示其影响机制,对极度恶劣热环境条件下石英/氰酸酯复合材料透波性能评估分析、热防护设计等具有重要意义。利用激光作为外热流加载手段,对石英/氰酸酯复合材料进行激光辐照烧蚀实验,对实验前后的介电常数进行了测试。为分析介电常数变化机制,对石英/氰酸酯复合材料激光烧蚀前后的表面产物进行了透射红外光谱、XRD测试,对实验后的石英/氰酸酯复合材料表面进行微观形貌观察,并对氰酸酯和石英纤维进行了热失重测试。结果表明:与初始状态相比,激光烧蚀后的石英/氰酸酯复合材料在7～18GHz范围内的介电常数为6左右,增大近1倍。分析认为激光烧蚀对石英/氰酸酯复合材料电性能的影响机制为:在激光辐照作用下,材料吸收激光能量升温,使氰酸酯树脂基体发生热分解、裂解等变化,在表面原位生成具有导电能力和岛链状态的炭黑物质,致使发生烧蚀炭化石英/氰酸酯复合材料的介电常数增大,将增强对雷达波的吸收。同时烧蚀形成的粗糙表面状态和疏松状态对电磁波的反射、散射作用增强,可进一步削弱石英/氰酸酯复合材料的雷达波透射能。

In order to obtain the influence of laser ablation on the electrical properties of quartz fiber/cyanate composite and reveal the influencing mechanism,it is great significance for the evaluation and analysis of wave transmission performance and thermal protection design under extreme harsh thermal environment.Using laser as an external heat flow loading method,the laser ablation experiment of quartz/cyanate composite was carried out in this paper,and the dielectric constant before and after the experiment was tested.In order to analyze the change mechanism of dielectric constant,the quartz fiber/cyanate composite surface products after laser ablation and quartz fiber/cyanate composite were tested by transmission infrared spectroscopy and XRD.The ablation surface of quartz fiber/cyanate composite irradiated by laser was observed by SEM.The thermal weight loss of cyanate and quartz fibers were also tested.The results show that the dielectric constant is about 6 and nearly 1 time higher than the initial state in the range of 7-18 GHz.The influence mechanism of laser ablation on the electrical properties of quartz fiber/cyanate composite is as follows：The absorption of laser energy makes the cyanate thermal decomposition and cracking,the formation of carbon black,which is conductive ability and the chain state in situ on surface,the dielectric constant of the ablation sample increases,the radar wave absorption capacity of quartz fiber/cyanate composite that is ablation state will be enhanced under this condition.At the same time,the rough surface and the loose stateformed by ablation will enhance the reflection and scattering of electromagnetic wave,which can further weaken the radar wave transmission capability.